New unable to access External sd when connect with USB

I recently install MIUI ROM on my galaxy s2 I9100, miui 2.10.26.v2.
My problem is when I connect my phone with my PC using USB cable I can't access my External sd card, it only shows internal sd card. I can access external card in my phone but not on my PC.
Help me to rectify it. Otherwise I love this ROM it is amazingly beautiful & fast I don't want go for any other ROM just because this single problem.

If you enable the USB Storage on your phone when connected to your pc, it's normal to be not able to reach that memory.
In fact the partition (SDCard) is unmounted in your phone to let your PC accesses it.